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Noticed something curious on the 'Z Axis Calibration' page in nanoDLP...
Please anyone comment on the following.
-I home the build plate; Under 'Platform Information' the 'Current' level is indicated 0.000000 mm Pulse 0 (This looks good)
-I raise the build plate using the 'UP 1 mm' Green Button; 'Current' level is now 0.999000 mm Pulse 533 (Not 1.000000 ?)
-I raise the build plate using the 'UP 1 mm' Green Button; 'Current' level is now 1.998000 mm Pulse 1066 (Ummm?)
-I raise the build plate using the 'UP 1 mm' Green Button; 'Current' level is now 2.998000 mm Pulse 1599 (Meh!)
Terminal Output (Just for shits and giggles):
ok
G28
G90
ok
ok
G1 Z1.00
ok
Z_move_comp
G1 Z2.00
ok
Z_move_comp
G1 Z3.00
ok
Z_move_comp
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Hi Stan,
The smallest movement on your printer depends on type of actuator, stepper motor and micro-stepping. For your printer, smallest movement is around 0.001874922mm, so for 1mm movement your actuator could actually move to 0.999333426 or 1.001208348 and not 1mm. Also consider rpi's processor is 32bit which some rounding happens for the float numbers. By increasing resolution artificially you can make nanodlp moves to exact 1mm but in reality it would not happens.
Nanodlp internally keeps everything as pulses and every movement calculated from absolute values, so during printing these small differences will get corrected as much as possible but it is not possible on manual movements.
At the end for above gcodes, everything related to movements being handled by RAMP board so nanodlp's internal calculations is not matter at all.
We are already on 64bit float for positioning internally but on display side it use 32bit float, even 128bit float would not make any effect movements even for direct control. Just numbers will be more accurate on screen and but they would never be 1mm,2mm,3mm...
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